A variety of conduit benders for bending different types and sizes of conduits have been utilized for many years. Many of these conduit benders include a generally-circular shaped shoe and a roller assembly. The circumference of the shoe often includes a plurality of channels of different sizes to receive conduits having various diameters. A gripping member is provided at a leading end of the channel and grips a portion of the conduit. As the shoe is rotated, the roller assembly provides a resistive force as the conduit is bent around the shoe to desired degree.
In order for the operator to bend the conduit to a desired angle, the operator must know the type of conduit to be bent (e.g. EMT, IMC or Rigid), the size of conduit to be bent (e.g. 1″, 1¼″, 1½″, or 2″ diameter), the bend starting point, the bend ending point, the elasticity of the conduit to be bent, and the wall thickness. Utilizing the above criteria, the operator determines the necessary bending operation to achieve the desired bend in the conduit. For example, the operator must determine how far the shoe should be rotated. At times, the conduit must initially be bent past the desired bend angle to account for spring back of the conduit. In addition, at times, additional support rollers will be needed to provide a greater resistive force for bending the conduit. To assist in making the proper bend operation, look-up tables are utilized. These look-up tables allow the operator to make a determination regarding the specifics of the bend operation based on the properties of the conduit to be bent. Proper selection and use of the look-up tables are critical in order to obtain the proper bend instructions. Other conduit benders include a processor and allow the operator to input characteristics about the conduit to be bent along with the desired bend information. The information is typically input using a number of switches and/or dials. The processor is configured to determine the necessary bend operation which will achieve the desired bend. With these conduit benders it is important that the operator correctly inputs the information.
The process of using look-up tables and setting dials and/or switches prior to bending requires time consuming steps and are subject to operator error. Often one or more parameters is overlooked or set incorrectly, resulting in bending mistakes and thus wasting materials and time.
It is sometimes preferable to bend conduit in a vertical plane and at other times preferable to bend conduit in a horizontal plane (i.e. a table top configuration). In order to provide versatility, conduit benders include a frame supporting the shoe assembly which is pivotally connected to a base. This pivotal connection allows the frame to be rotated relative to the base to provide for bending of the conduit in either a horizontal or vertical plane. The pivot axis is positioned perpendicular to the shoe shaft, and is further positioned away from the shoe in order to provide a clear path to feed and bend the conduit. With the pivot axis perpendicular to the shoe shaft, the operator rotates the frame 90 degrees about the pivot axis to alternate between the horizontal and vertical bending positions. Benders provide two shoes in order to accommodate various types and sizes of conduits to be bent. With two shoes mounted to the frame, the pivot axis is positioned between the shoes at or very near the center of gravity to minimize the effort required by the user to pivot the shoe between the vertical and horizontal positions.
Often benders are provided on a wheeled base which allows for easy movement of the bender assembly between bending locations. The wheeled base typically includes casters having wheels which can be pivoted relative to the bender frame. In order to prevent the bender assembly from rolling during the bending operation, brakes are provided on each casters to prevent the wheel of the caster from rotating. Actuation of these brakes must be performed at each caster. In addition, upon actuation of the brakes, the casters often still pivot (at least slightly) unless a swivel lock is also provided. A disadvantage of swivel locks is that clearance must be provided for the swivel locks and each swivel lock must be individually engaged.
The present invention overcomes problems presented in the prior art and provides additional advantages over the prior art. Such advantages will become clear upon a reading of the attached specification in combination with a study of the drawings.